Electromechanically-controlled telephone system



' May s, 1928. 1,669,368

F. ALDENDORFF ELECTROMECHANICALLY CONTROLLED TELEPHONE SYSTEM Filed Jan. 24. 1925 5 Sheets-Sheet 1 F. ALDENDORFF ELECTROMECHANICALLY CONTROLLED TELEPHONE SYSTEM May s, 1928.

Filed Jan. 24, 1925 5 Sheets-Sheet 2 May 8, 1928.

F. ALDENDORFF ELECTROMECHAN ICALLY CONTROLLED TELEPHONE SYSTEM Filed Jan. 24, 1925 5 Sheets-Sheet 3 WOW MWN

May 8, 1928.

F. ALDENDORFF ELECTROMECHANICALLY CONTROLLED TELEPHONE SYSTEM 5 Sheets-Sheet 4 Filed Jan. 24, 1925 MM M U w p-M F. ALDENDORFF ELECTROMEGHANICALLY CONTROLLED TELEPHONE SYSTEM May 8, 1928.

Filed Jan. 24, 1925 5 Sheets-Sheet 5 fzzvezzidr 31 mm n/ Patented May 8, 1928.

UNI ED S ATE 1,669,368 PATENT ounce,

rnrrznnnnunonrr, or nnntm-witmnnsbonrg GERMAN CHARLOTTE ALDEN" 110mm, HEIRESS or SAID FRITZ ALDENDORFF, DECEASED.

ELECTROMEGHANICALLY-GONTRbLLE-D TELEPHONE sYsrnmfi Application filed January 24,1925, sen-a1 No. 4,380, and in Gersh in-arms; 1924."

This invention relates to telephone systems operating with selectors and'to-selector;

arrangements for"suclr'systems; A feature of the invention consists in anarrangement accordingto which; after a numerical selec tion, that i'sa selecting functioncontrolled by numerical impulses, a nonnu1nerical selacuna is performedby a selecting device that',fin casesin'which groups of trunk lines in a bundle of trunks are engaged jumps over the busy groups and only Commences testing the trunks individually in a group containing a tree trunk. The function of jumping over busy trunk groups and thereupon testing the trunks individually may takeplace in thegroup selectingstage or in the final connecting stage of the connect ing function The numerical and non-num erical selectingt'unctions may each be performed with the aid of several sets or one and the same set of brushes. The numerical consists in' a seloctor provided with a hollow shaft towvhich is fixed 'a ratchet wheel that is locked in its initial position against rotary motion by a stepping pawl, theselector being further provided with a brush carrying shaftadapted to be rotated in the hollow shaft and to be coupled to the ratchet wheel by a coupling member. I The coupling of the brush carrying shaft may take placehetore the ratchet isstepped round.

The invention further relates to a selector whose brush carrier is first moved out of its initial position into an off-normal posi t-ion andthen from the ofi normal position back to the initial position by a single spring. The'spring is rewound after the brush carrier has been returned to its'initial position by a separate rewinding member.

impulses.

The selector may be provided Witha longitudinally movable rod, shaft or the like carrying a tappet which, during the longitudi nal return motion of the'shai't-"into its axiall normal position, is initially pressed by a spring against a glidingsurfaceand, after the rod has reached the'said initial position, the said spring also turns the rod into its radial norma-l position. Thebrush carrier may be arranged to perform a slow vertical movement,"then a rapid rotary movement and thereupona slower rotary movement A further feature of the invention consists in a selector Whose brushes are controlledby anelectric coupling that receives current impulses through contacts controlled. by a cam. After the brushes have been set onto a certain'group of contacts the cam Wheel is rot'ated by a stepping wheel until the brushes have reached ai desired. contact set.

The inx ention further relates to a group selector provided with brushes Which when they hunt for tree trunks, jump over each of trunks that is'busy and only commence testing the trunks individually when they reach a group; inwhich there is still a tree trunk. The brush shaft of the group. sew-1 iector may be moved longitudinally an d'then rotated at a high speed and thereafter at a lower speed; The brush carrier is first moved in one direction withthe aid of numerical' impulses and then in a second direction undenthe influence of further nu- I mericalimpulses beforeit executesits n0nnumerical selecting function. The group: selector may firsthe set onto a group oi? lines under the influence of two series oi mullet-1 cal impulses and then jump over busy sets of trunks in the selected group and thereupon tcst thetrunks individually in the group finally reached. Theinvention l urther relates to a connector whose brushes after being setonto a certain group by being moved iIl'tWO diifn ent directions under the influence of numericalimpulses, jump over busy sets of lines" in the group finally lOU reached and only then commeneetesting the lines individually. A further feature of the invention consists in aconnector Whose brushes are set onto thedesired line under the influence of three series of numerical A further feature of the invention consists in a connector Whose brushes firstexecute longrot-ary steps and then short rotary steps in being set onto adesired numlit) her and then, on reaching a number cornprising several lines, are automatically rotated until they reach a free line leading to the subscriber with several lines. When er;- ecuting their long steps, for example rotary steps, the brushes may be impelled a spring.

The invention further relates to a selector whose brushesare rotated continuously at a high speed to the desired contact set where they are stopped by a retracting electromagnet armature. A particularly advantageous effect is attained when the electromagnet is bridged over or arranged to be bridged over by a condenser. The selector may be started and stopped by the same electromagnet. The brushes may be moved by a spring that is wound by a winding magnet. The winding magnet circuit may be controlled by a test relay of the selector. This circuit may be maintained closed during the motion of the selector brushes over the bank contacts of the selector. The circuit of the starting and stopping electromagnet may depend on a bank contact row and the circuit of the rewinding magnet may be controlled during the setting of the brushes by means of a relay and another bank contact row.

The invention relates further to telephone systems with line finders characterized by the fact that their voice current brushes are set upon a calling line by a retracting armature engaging with a tooth of the brush carrier that corresponds to the calling line. The stopping electromagnet of the line findor may be bridged over by a condenser in order to accelerate the falling back of the electromagnet armature.

A further feature of the invention con sists in a connector that executes long and short rotary steps and is characterized by the fact that in addition to the customary voice and test contacts, it is provided with bank contacts for subscribers having several lines, these bank contacts being wiped by a brush through which, when a line is engaged, a circuit is closed that causes the rotary magnet to continue rotating the brushes until a tree line is found. The long rotary steps of the brushes may be produced by spring power. The circuit of the magnet that controls the long rotary steps may be closed and opened by a contact operated by a cam disk. The contact operated by the cam disk is connected to contacts of the numerical impulse relay.

A further feature of the invention consists, in a telephone system in which the line finders, group selectors and connectors have brushes or wipers which are moved by spring power and whose movements are controlled by an electromagnet without the aid of auxiliary switches. Still another feature of the invention is a telephone system in which switches are employed having wiper carriers that are moved in two directions and whose wipers are set onto a desired line or trunk by spring power. In a telephone system according to the invention the arrangement is such that a calling party who has been connected through to a numerical switch cannot affect the wipers of the numerical switch until he has sent inat least two numerical impulses. The impulse transmitters or dials of the calling stations are arranged so that when the impulse transmitter is set so as to send one wi er setting impulse into the numerical switc two impulses aresent over the line to the exchange.

Another feature of the invention consists in a selector with a longitudinally movable rotary shaft that is guided during its longi tudinal movement in a stepping wheel, means being provided for preventing it from turning relatively to this Wheel.

The invention is shown by way of example in the drawing in which Figs. 13 illustrate a selector or switch with a longitudinally movable brush carrier (shaft) which, after it has been set relatively to a certain row of bank contacts, is first caused to execute a large step or steps at a high speed under the influence of a spring, and thereupon executes short rotary steps.

Fig. 2 brush shaft.

Fig. 3 is a plan view of a stepping wheel provided with a coupling member and Fig. t is. a section on the line IV-IV of the brush shaft as seen from above.

Fig. 5 shows the circuits of a line finder,

Fig. 6 illustrates a group selector,

Fig. 7 a connector and Fig. 8 shows a modified group selector.

Fig. 9 shows circuits by which a numerical. impulse receiver (group selector, connector) is prevented from being affected by a calling line connected to it until at least two numerical impulses have been sent by the calling party through the impulse relay.

liig. 10 to 12 illustrated details of the shaft locking mechanism.

Fig. 13 is a detail view of the cam operated springs with the operating cam in nor mal position.

The selector shown in Fig. 1 comprises a shaft 1 which carries brushes 2, only one brush being shown. The shaft 1 is adapted to be shifted longitudinally in a bushing 23 attached to a cam disc 4 (see also The bushing 3 has a pin 5 along which a groove 6 in the shaft 1 slides so that the shaft 1 can move longitudinally in the cam disc t but cannot be turned relatively thereto. The bushing 3 is journalled in another bushing 7 to whose upper end a toothed wheel or stepping wheel 8 is attached. Pivoted to the stepping wheel 8 by a pin 10 is is a plan view of a cam disc and that rotates with the brush carrying an arinature or coupling ineinbr 9f The upwardly extending part 11 oft-he coupling ineinber protrudes, When the selector is in its nor; al position, through a slot 13' of the stepping Wheel and into aslot 12 of the cam disc In this position of the coupling member a locking nieinber 15 pivoted at 14,

-is lifted out of the slot 12. The locking iii) member 'is arranged so that when the cam disc's isturned it can only drop into the 'slot12 but not into the narrower slots The bushing or sleeve 7 and the cylindrical magnet 17. Connected to the bottom end ofthe' sleeve 7 is a spring box 21 one end of whose spring 22 is attached to the sleeve 3 Whilst its other end is attached to the box 21 and through this box to the sleeve 7. When the selector is addressed or in its normal position thespring 22 is wound up and the sleeve 7 is locked against rotation in the direction of the, ar-

row by'a deteiit that engages with the Wheel 8.

The inner sleeve 3 and the shaft 1 longitudinally displaceable in the same is locked against rotation in the direction opposite to the arrow 23 by the clutch 11 of the coupling member 9.

When current impulses are sent through the lifting magnet 2a the brushfshaft 1 is lifted step-by-step and held in its raised position by the holding pawl 26. After the brush shaft has been raised to "the desired height its rotation is brought a'bout'by excitation of the cylindrical inagnet 2-1 which pulls the miniature 9 with the clutch 11,

, downwardly and thus liberatesthecam disc 4t so that this latter is turned by the spring box until the clutch 11 is released by the magnet 14 and permitted to enter a slot in the cam disc, say 16 The de-energization ofthe coupling magnet 17 preferably takes place as soon as the advancing edgeofthe .slot reaches the front edge of the clutch 11 so as to give the latter sufiicient time" to enter the slot-16 even if the cam disc is rotated very quickly. After the min disc4 has been coupled with the'wheel 8 current impulses are sent through the rotary magnet 27 and this turns the Wheel and therefore also the (3 8111 disc dand alsot-he bruslishaft 1 step-by-step until the brushes 3 have reached the desired set of bank contacts. The locking niein'ber 15 Will now be lying on the top surface of the cam disc 4. To retnrn'the brush" shaft into its" initial position; the magnet 1 17 "againenergiz aed to Withdraw the clutch 11 from theslot in the C3.lll disc. The spring boX now iotates the sleeveB Wiiilitl'lfi ca'in disc dand the shaft with its brusl'ies in the same direction as be-' 7 fore until a pin 28 at the'bottoin end'fof the shaftstrikes against-a slide Way29 placed nearthe shaft. Inthis' radial-pos'i-I tion of the shaft the holding pawl 27 will register with the channel BO'of the toothed section 31 of thefshaft and the latter Will new drop until the pin 28 leaves the slideivay 29, whereupon the spring box will turn the shaft furtheraround until it is stopped by the locking ine nbe'r lfidropping into these broad slotj12 of-the can'r disc 4. Finally the nia'g iet 17 is dc-e'ne'rgizedso that the clutch 11 entersthe slot 12 and pushes the locking nieinber' I5 OiiUO1 'tlIBCamdisc. When the" locking "ineinberis' thus lifted a leaf spring 35" 15 (Figs.* 10, 11, 12) moves towards the right (Fig; 11) so that when'tlie cl'utch 11 is again pulled down -bythe magnet 17 thespring 15 'will rest upon the topsurface of the cam disc 4: and prevent the lo'cking ineinher from entering the saine'unti'l it has ex ccuted' almost an entire i'ei'olution that is until the Wide slot 12 (Fig; 2) again reaches the locking ineni'ber.

The'cain disc 14 in a connector is'provided With ten projections32. In a groupselecton Fig. 6, Whose brushes only perform a non nuinericalj selection, during their rotation the cain' dischas only a's'ingle projection- 32";

but in groupse'lector whose bi ushes' also' we perform a numerical selection during their rotation there a'reseveral projections 82 on the-cain disc. 1 In cases in which the group" selector after executing a iuinerical sele'c tion during its rotary movement; juin 'as'past 5 groups of'e'ngaged lines-it is provided with stepped "PIOJGCUQDS 32 etc. shown in Fit-r18." I

The line tindershown in ;Fig. 5 has a.

brush carrier which is also arranged to be no rotated by a spring The brush carrier is i'ioriiially lockednnd when it is unlocked the'brushes are Whirled round by the spring without stopping until they reach the'bank contact set of the callingsubscriber.

The further details ofthe operation of the 'arious switches or selectors Will appear more fully hereinafter in the description of the functions which take placeinthe estaiblishinent of a connection between a*ca1ling- 2 and called subscriber.

ItjVlll befass urned that a telephonesystem comprises line finders, Fig; 5,"gr0up selectors, Fig; 6 and connectors, Fig.7, each'bank contactfrow of the select'orsfhaving 20 50 12'5 outgoing circuits or trunks while each bank contact row of the connectors in each con? nector has contactse'ts connected to 50 sub sc'r'ibers.lines. The coniiectorsare arranged so that whendlieir brushesar'e set ento" a "0 are opened and contact 115 is closed.

subscriber who has a plurality of exchange lines the connector will hunt automatically for a tree line.

The selectors are adapted to receive one series of numerical impulses and the connectors receive series oi. numerical impulses.

Assume that a connection is to be made with a subscriber having several exchange lines and whose number is No. 233' When the calling subscriber raises his receiver a current flows from the positive pole through the line relay 102, contact 10301 the cut-oil relay 1, wire 105, sub-station 101, wire 106, contact 107 to the negative pole. The line relay is energized and by opening its contact 108 designates the bank contact set of the calling subscriber, i. c. this contact set is designated by removing the positive potential from the designating contact 109. At the same time the relay 111 of the trunk finder V is energized by a current through the contact 110 so that the contacts 113, 11 1 A current now flows from the positive pole through 115, brush 110, oil-normal contact 117, starting magnet 118 to the negative pole. The magnet 118 attracts its armature 120 which is pivoted at 11.9 and thus releases the wheel 121 thus permitting it to be whirled round by the spring 100 at a high speed together with the brushes 122, 123, 12 1 and As soon as the brush carrier or the wheel 121 leaves its normal position the 011'- normal contact 117 is opened and the other oil-normal contacts 120,127 are closed. The magnet 118 now receives current through the bank contacts 128, 129' belonging to non calling lines or busy lines, these contacts being connected to the positive pole through relay contacts whichcorrespond to 108. As soon as the contact set 109 of the calling line reached by the brush 122 the magnet 118 is deenergized. The designating contacts 109 etcare displaced relatively to their associated bank contact sets in a direction opposite to the direction of rotation by the brushes. The falling back of the armature ot the magnet 118 is accelerated by the condenser 130 connected in parallel to the magnet. so that the pawl 1 0 engages with the wheel 121 and stops the brushes 123, 1241, 125 on the contacts 131, 182, 133 and the relay 14.0 is energized by a current flowing from the positive pole through contact 115 of the relay 111, 116, 1 10, 123,131, cut-o1i' relay 10 1- to the negative pole. The relay 140 opens the contact 141 and closes contacts 143, 14 1. If the brushes 122, 123, 124-, 125 should have overstepped the contact set 109, 181, 132, 183 of the calling subscriber, the rotary magnet 1 will receive current impulses that flow from the positive pole through contacts 126, 145, 1 11, contact 1416, interrupter 1 17 to the negative pole. The magnet 15% then steps the brush carrier 121 backward until the brush 123 reaches the contact 131 and the relay 1 10 is energized. The circuit of the stopping magnet 1 15 is then opened at con tact 1 11.

The calling subscriber is now connected through the brushes 124, 125, contacts 1 12-3, 11-1,-contacts 3, 201 (Fig. with the impulse relay 205 so that this latter receives current that flows through the contacts 203, 20 1, 113, 1 1 1, brushes 121, 125, over the subscribers line 105, 100. The impulse relay closes its contacts 206, 207 and a circuit is closed extending through 200. release relay 208, resistance 200 to the positive pole so that the release relay opens its contact 210 and closes the contacts 211, 212. By the closure of the contact 211 the positive pole of the battery is connected through contact 1 12 directly to the low resistance winding 1 1 1 of relay 110, whereby the con tact 181 and the other corresponding contacts oi? the other line finders of the same group are rendered busy. The closure of contact 211 also results in the energization of relay 150. This relay closes at its contact 151 a locking circuit for itseltthat extends through contact 126 and at its contact 152 it also disconnects the magnet 118 of the line finder from the brush 122. The energization of the relays 208, 1 10 and 101 takes place practically at the same moment and by the energization 01 the relay 101 the line relay 102 is cut oil and thereby caused to open the circuit of the relay 111 at con-- tact 110. This results in the closure of armature contact 114 and the magnet 153 now receives a current impulse which flows from the negative pole through the interrupter 153 111, 153, bank contact 1541, olf-normal contact 156 to the positive pole. The impulse sent through the magnet 153 results in the wipers 155, 116, 156 being rotated to the next bank contact set 157,158, 159. If this contactset also leads to a busy trunk the magnet 153 receives another impulse which'steps the wipers ot the trunk tinder 112 further around. This stepping function continues until the brush 155 reaches a wire that is not connected through a contact 126 to the positive pole, i. e. which belongs to a tree trunk. This tree trunk is then usedby the next caller.

The calling subscriber sends in two numerical impulses which result in the armature of the impulse relay dropping back twice, so as to send two impulses from the negative polethrough 212, 218, 21st, lifting magnetv 1 to the positivepole. The brush shatt with the brushes 215, 216, 217, 218 thus liited two steps. At the first step the vertical oil-normal switch 219 is closed. After the two numerical impulses have been sent in the armature oi' the impulse relay 205 remains attracted and keeps the contact 207 closed for an extended interval thus Jun messes short-circuiting the winding of the change ,over ,relay220, for a comparatively long period so that'this ,relayalloivsits armature to drop back sons to close the contact 221 which results inthe relay 222 being energized by a current that flows from the nega tive pole through 221, 219 to the positive pole. The relay then opens its contact 2 14 and closes coi' 'tact 223 to energize v the uncoupling magnet 2 by a current that ,fiows l l'Oll'l jllllC, negative pole through 223,

niagnet 2, relay contact 224, ot'E-normalcoir tact-225 to the positive pole. The brush shaft which is similarto 1, Fig. 1, with the ra n disc 226 (similar to 4, Fig. '1) is now uncoupled.fron'i the stepping Wheel (siinilar to 3, Fig. 1) so that the spring box turns the shaft with its brijishes and the cam disc out of: its rotarynormal position. As soon as the shaft. leaves this position the contact is opened and contacts 227,228 ofthe nit-normal. switch 234 are closed.

If all oftheltrunlzs connected to the bank contact sets in thearc'235 are engaged, re lays which belong to these trunks will close a chain of contact-S230, 231, 232, 233' and keep rt-hei uncoupling magnet 2 energized by a current .that fioivs from the'positive tact 229 that is closed by the projection 32 of" the cam disc as soon as the brushes comuience rotating, 2 24, 2,. 223 to the negative.

A pole. When the brushes reach the first set of contacts 235, 236,237, 238 the spring to eii'ect a short interruption of the current flowing through the uncoupling mag- ,1 etl2. This shortinterruption does not, v r

the tree-i1 are busy solthat the arcuate contact 240 Wlll be connected by {DQ113111 of relay contacts to the positive pole and theun- 223, the Wipers will. be rotatedfurther and the brush. 218 will reach the arcuatecontar t 242 1 243, 244, 245 emanating from the. are

disconnected lrointhe positive pole and Whenthc brush 218 1caches the arcuate contact: .the uncoupling magnet 2' W111 be tie-energized;sopthat, the clutch vvill enter into one of the openings in the cam disc 226 and stop the brushishaft' so as to. arrest the set of brushes on the contact set 248, 249, 251. 'Tlierelay 252W1ll now be eneriZedin' a circuit extend ng froingthe positiye pole through 227, ire 253, contact 248,

pole through the contacts 230 to 233, ,coni leaves the, projection or cam 32 and ,the contact 229 1S thus momentarily opened H group busy. however, suliiceto enable the armature of the uncoupling magnet 2 to. {all back sothat the coupling magnet will continue to receive current through the brush '2l8xand 224, 2,

Assuming further that the trunk brush 218, contact224, magnet. 2, contact 223 to the negative p'ole. The relay 2521 at its con t closes filOfOklIlgl circuit for'it- .self and by its contact 255 itpprepares, a circuit for .the uncoupling n mg'ne't 2. fAt its contact 256 it closes the circuit of the stepping;- magnet 3, which .magnet 'nowieceives i'mpu "flowing from the negative pole through the interrupter258, contact257, contact 256, inagnet 3 to the positive pole. The brushes .215, 216, 217, 218, are now turned step-by-step until they reach abank contactsetvin the are246,\vhich is connected to a 'free trunk. On their reaching a free trunk for example 243, 244, 245,21 current flows from the negative'pole tl1rougl1 @212, testrelay-259, testbrush 217, test Wire 245,

vertical o-fl nornial 60111 3015, 203 of the idle.

connector, resistance .302 to the positive pole.

A test relay 259 is energized and atits contact 260short-cn'cuits a part of its W nding,

While opening the circuit of the rotary magnet 3 at contact 257 and closing the c rcuit of the auxiliary relay 262 at contact 261 ithe iinpulse relay 305 ofthe connector Fig.

.The impulse relay 305 closes its contact 306,307 and opens its contacts 308, 309. By are closure of contact 306the release relay310 isflenergizedfin acircuit extending from the negative pole306, 310, 311 to the aositive, role. The release rela closes its 1 V i l Y contact'312 that belongs to a chain of con tacts which, when all the similar contacts belonging to other trunks or conneetorsfof the same group are closed renders the trunk The release relay also closes contact, 313 j 7 which establishes r aconnection betweeirthe tcstivire 245 and resistance 302 and the positive polethat is independent of thecontact 301. t also ,closescontacts 314, 315 and opens the contacts 316, 317.

,The callingosubscriber 'nowsends in three hui'idreds impulses vthus causing three closuresot the contact 309. in quick succession so that threeini pulsesflow; from" the negative pole through 315,,309, 318,1liftii1g agnet Z1 1 -.the positive pole.

thefchangeover relay 319, whichp vas enerlgiaed during the series of impulses bya cur- 246is free, the arcuate contact242 will be I ,trom the 'neg-ative polethrough ofi-norinal contact 323, left hand Winding of. 322,,321 to thenpositive pole. fljhevrela-y222lcloses a locking circuit for witself through contact and at contact225 preparesa circuit for the uncoupling magnet 2.

' The calling :subscribernhyv sends three lit).

v lThe brush v his thus lit-ted threesteps ln the mterval enusing after the, series of an'lpulses 7 next.

impulses.

tens impulses. At the first tens impulse the uncoupling magnet 2 is energized by a current flowing from the negative pole through 315,309, 325, 326, contact 327, uncoupling magnet 2 to the positive pole. The uncoupling magnet uncouples the cam disc 328 and the brush shaft from the-stepping wheel (similar to 8, Fig. 1) so that the cam disc 328 is rotated together with the brushes 329, 330, 331, 332. As soon as the cam 333 leaves the contact spring 334 thecurrent through the uncoupling magnet 2 will be interrupted even if the impulse through contact 309, 325 has not ceased at that moment so that the clutch will enter an opening in the cam disc 328 and stop the brushes 329 to-332 as soon as they reach the bank contact set 335 to 338. The contact 344 is now pressed by the cam against the contact step and the clutch enters another opening of the cam disc and stops it when the next cam 340 reaches the spring 334. The third tens'impulse now energizes the uncoupling magnet a third time whereupon the clutch enters the next hole in the cam disc and stops the brush 329 to 332on the bank contact set 341, 342, 343, 344. It is to be noted that the spring which rotates the cam disc with the brushes is adapted to turn the brushes at a speed at which they will always reach the The cam next to the one engaging with the contact spring will always reach the spring in the interval between two'tens On the other hand the tens impulses follow one another so. quickly that a single retraction of the armature oi": the impulse relay 305 will never send more than one impulse through the contact spring 34 while it is engaged by one and the same cam on the cam disc.

In the interval ensuing after the series of tens impulses the changeover relay 319 is again (lo-energized by its being short-circuited at contact 307 and the relay 345 is energized by a current flowing from the positive pole through 346, 345, 347. contact 348 which is closed at the initial rotary movement of the cam disc 328 to the negative pole. The relay 345 closes its contacts 349., 350. 113 contact 348 a circuit is pre pared for the relay 351 which is closed when the changeover relay 319 is energized when the units impulses commence coming in. The relay 351 closes at its contact a locking circuit that extends through the contact 314.

When the units impulses are sent in cur rent impulses flow from the negative pole through 315, 309, 350, rotary magnet 3, oh?- normal contact 353 to the positive pole. The brushes are hereby stepped round and as,

1,eee,aes

in the case under (:(msideration the subscriber No. 2331, who has several lines, is being selected the brushes will be rotated one step so as to be set onto the bank contact set 354,355, 356, 357. It will be assumed that the subscribers first line is en gaged, this being so the rotary magnet 3 will receive further impulses for the following reason: When the changeover relay is (lo-energized after the. units impulses, or in this case the one units impulse, have been sent in the positive pole is connected through 346, contact 358 to the test relay 359. It the line is engaged the test relay 359 will not be energized. Therefore a relay 360 is energized by a current that flows from the positive pole through 346, 358, contact 361, relay 360, brush 332, contact 354 to the negative pole. The rotary magnet 3 now receives impulses that fiow from the positive pole through 353, 3, contact 362, contact 363, contact 364, interrupter 365 to the negative pole. The brushes are thus rotated further stepby-step until a tree line is reached when the relay 359 will be de-energized so that the relay 360 will also be ole-energized by the opening by the contact 361. The bank contact sets that belong to a subscriber who has several lines lie next to each other in the contact bank and the contact wiped by the brush 332 in the last bank contact set of the group is not connected to the negative pole like the other contacts which are sim ilar to contact 354 so that the relay 360 will be dc-energized'to open the circuit of the rotary magnet 3 when the brushes reach the last line of the group even if this last line is also engaged.

lVhen a ireeline belonging to the called subscriber-is reached the test relay 359 is energized by a current that Hows from the positive pole through 346, 358, 359, test brush 351, test bank contact, cut-oft relay of the tree line found, to the negative pole. The test relay 359 opens the contacts 361, 363, and closes the contacts 371, 372, 373. By the contact 373 the circuit of the ringing relay 374 is closed and it periodically closes the contacts 375, 376 so that the ringing current generator 377 sends ringing current to the called line. ll hen the *alled. subscriber responds the relay 378 energized to open the circuit of the ringing relay 374 at contact 379. The relay 378 closes at its contact 380 the circuit of a relay 381 which closes a locking circuit for itself at contact 38 2 and at its contact, 383 prepares a connection betweenthe contact 384 or the negative pole and the right hand end of the winding or the release relay 310. lVhen the called subscriber replaces his receiver the relay 378 allows its armature to drop back so that the release relay 310 is short-circuited through 384, 383. The armature ot the release relay then drops back and at contact 314 opens in 'and the brushes further around until the pin,lil e 28 (Fig. 1) strikes against a stop or slideway like 29 (Fig; The rotation of the shaft is thus stopped with the groove 3O registering with the holding pawl 26,'Fig. 4. 'jTl'ie-sliatt and the brushes now drop into their "lowest position, and in this position the pin 28 can berotated past the stop or slide'way 29; The spring-box therefore turns the shaft further around until the B -locking member 15 (Figs; 1, 10, 11 and 12) dropsinto the wide opening 12 (Fig. 2) and finally stops the sha it. Thebrushes will now: be positioned relatively to the contact bank as shown in- F ig. 2 and the shaft with "the cam disc 328 will be in itsnormal position so that a recess 828 of a ca1n*-328 'at tee-lied to the 69.11] disc 328 will register-with the bent end 353' of the contact spring 853. -'Tlie spring 353 is,however, as yet prevented from dropping into the recess328 because it further 021111828 connected with the,

toothedwheel8, Fig. 1, hasnot returned to 'its normal position. 1 But when this wheelis else restored a recess 328 will be in line i with the recess 32S and allow the contact] tion nndnt contact 227 01301181118 locking" spring 353 to move into its normal position. y The restoration of the stepping-wheel -8 is effected by the rotaryniagnet' 3 which on the -de-energization of the release relay-310 receives current impulses which flo'w from the negative pole through the interrupter 365,

'reley259 allows its armature t0 (ll01) hack. As the calling subscriber has replaced his TGCGIVOI' the impulse relay 205 is -de-energized and the release relay 201 isshort-eir- 'cuited by the contacts 280, 281. The release relay will therefore have closed its contact 210 and thus completed the circuit of the uncoupling magnet 2 which extendsfrom the positive pole through-210, 228, 255, 2, 223 to the negative poleof the battery. The spring box turns thebrush shaftuntil its pin (similar to 28, Fig. 1) strikesagainst the stop 29 and'the channel 30registerswith the holding pawl 226. I The brush shaft then di ops'until the pin 28,"Fig. 1 is outofv tl'ie reach of the stop or slide way 29 whereupon the spring (22, Fig/1) impartsanwid- 1 -clitional small rotary movement to the sliaft to enable the holding pawl 26 to engage with the circular teeth31. \Vhenthe shaft has reached its bottom position it. opens the locking" circuit of the relay 229 by the contact 29. On the dc-energization of-the test relay 259 the circuit of the rotary magnet- 3 was closed at contact 257 and therotu 'y magnetis thus ceused to operate until the stepping wheel (like 8,""Fig. l) of the selector turned intoi'ts initial position so as to fully rewind the spring box. When the cam disc 226and the stepping Wheel hfive both reached their normal positions the switch 234; moves nto itsnorinal posicircuit oftlie? rel1y252'whieh'is de-cner gizedhnd opensfthe rotary magnet circuit at contact 226. The group selector is thus restored to its normal position in which the uncoupling inagnet 2 is (lo-energized and "'tlie i'l'ocking member lfi is lifted out ofthe contact 317, rotary nia netS, contact 353 to i the positive pole. WVhile the uncoupling Wide opening oitthe czi'in disc; By the openinn of contact 211 at thede-energizstion'ot relay 208 the loclring'circnit of relay 140 of the line finder,jFig. 5, is broken so thatfren'iagnct 2 is energized the wheel 8is now spring in the spring boX is 'fully'rewound i and when this isthe case-the recess 328 01? "thecain 32S connected t0 the heeljlS will be in line with the recess" 328 so that the bent end 353 .0f the spring 353 will drop 1 intothe two recesses 328 328 so as to open i the circuitsot the uncoupling; magnet 2 and "tl'iQ rotary mugnet The connectoris thus i restored to itsnormal position in which the spring of the spring box is completely wound up.

i If the callingsubscriberis first toharig neeti up the release relay circuit-319m o'penedat contact 398 ofthe impulse relay 8'05 and the restorine' operations al eady described I are meric al selecting functions are -'coijitrolled= bv lay 140 allows its armature to drop' back so as to close at contact 141 a circuit for. the

"pole. "The rcwinding inagnetl ifi now turns the wheel 121 ui'itil thespring 100 is "WOllTlCi up and the su 'itc'hlSiO is returned to 'its norfmal "position by the cum "191. -All parts which were engagedin the established" conon have now been returned to their initial or nornial positions.

Figfti illustratesn group-selector inwhi'eh numerical iinpulsesfonly afie'ctthe longitudinal movement of the brush shaft.

FiQQSshOWS a groupselector whose nutwo series ofnumerieul impulses. Thefir st series effects the raising of the brush shaft test wire 245 and the test relay 259, Fig 6,-

is interrupted at contzict313so thatlthe test and the second series cnusesthe shaft to execute longrotsry'stens. NVhen' the last longnun'iericzilly controlled rotary step has the calling subscriber sends the first series of numerical impulses into the group selector, Fig. 3, its brush shaft is raised. step-by-step by the magnet 412 that is energized by impulses I flowing from the negative pole through contact 413, 409, 414, 412 to the positive pole. While these impulses are flowing the changeover relay 415 is energized by a current which flows from the negative pole through 413, 415. 416 to the positive pole, for the brief short-circuit-ings oi the relay 415 at contact 407 do not cause this relay to drop back. In the interval that ensues after the first series of numerical impulses the changeover relay 415 is, however, short-circuited long enough at contact 407 to cause the relay 415 to drop back and to. close the contacts 417, 418. As the vertical o'tl -norn'ial switch 419 of the group selector is closed at the first vertical step of the brush shaft the closure of contact- 417 new results in the energization of the relay 430 by a current that flows from the positive pole through 417, 420, 419 to the negative pole. The relay 420 closes a locking circuit for itself at contact 421 and at contact 422 it prepares a circuit for the uncoupling magnet 423. When the calling party sends in next series of numerical impulses a corresponding series of impulses. is

sentthrough the uncoupling magnet 422 which flow from the negative pole through 413, 409, 422, cam actuated contact 424, con tact 425, 426, 423 to the positive pole.

It is to be noted that every long. rotary step 01" the brushes corresponds to an are like the arcs 430. 431 etc. In each such are of the contact bank there may be several groups of trunks. Two such groups are assumed to be provided in each are in the present case. The first group 1 in the first arc occupies-a part 01 the contact bank opposite to the arcuate contact 432. Corresponding arcuatc contacts 433, 434 are provided in the other divisions of the contact bank. If more than two groups of trunks are provided in each arc of the contact bank these arc uate contacts. serve to mark the trunk group opposite to the arcuate contact 432 asengaged it all. the trunks in that group are busy. When the calling subscriber sends in the second series of numerical impulses as described the spring 450 will. first ride upon a high cam, e. g. 32 at each impulse that flows through the contact 422 and the magnet 423. The contact 451 is thus closed and a circuit which is independent of the circuit through 413, 409, 422, 424, will be closed through 451, 425, 423. In this manner the uncoupling magnet 423 is always kept energized until the clutch enters the second next opening in the cam disc 452 and stops the brushes 453, 454, 455, 456 at the commencement of an arc, e. g. the are 430. Assuming that the first numerical impulse will have caused the brushes to be rotated in this manner to the first are 430 the spring 450 will now lie upon the first step 457 of the next cam tooth 32 and the contact 424 which was opened when the cam tooth 32 left the spring 450 until this spring was reached by the step 457 is now closed again. The second numerical impulse now flows and causes the brushes to take their next long rotary step so that they reach the contact set 458, 459, 460, 461 for example assuming that the second series of impulses is now terminated the relay 415 drops back again and at contact 418 closes a circuit that extends through 462, 463 to the negative pole. The contact 463 is closed as soon as the cam disc 452 leaves its normal position. By the energization of the relay 462 the uncoupling magnet 423 is connected through '26, 464, 465 to the brush 456. It the group of trunks corresponding to the arcuate contact 433 in the are 431 is engaged, the chain of relay contacts 466, 467, 468, 469 will be closed and the uncoupling magnet 423 will receive current flowing from the negative pole through 466, 467, 468, 469, 458, 456, 465, 464, 426, 423 to the positive pole. The clutch is thus energized and the cam disc together with the brushes is rotated until these latter stop at the beginning of the next group of trunks. It the first trunk in this next group is engaged the test relay 472 will at first not be energized but the relay 473 will receive current that flows through 473, 474, 475, 418 to the positive pole. By this means the rotary magnet 475 is made to receive current impulses that flow from the i'iegative polo through the interrupter 474, contact 476, magnet 475 to the positive pole. As soon as the test relay 472 is energized by a current that flows through 418, 475, 472, 455 and through a test wire that extends to another switch ahead the relay 479 is energize-d and the circuit of the relay 473 is interrupted at contact 474 and consequently the circuit of the rotary magnet 475 is also interrupted at contact 476. When the calling subscriber replaces his receiver the impulse relay 405 is tie-energized and shortly after the release relay 410 is also de-energized by being short-circuited at 408. The uncoupling magnet 423 now receives current flowing from the positive pole through contact 480, 463 to the negative pole. The shaft is then rotated by the spring box until its pin (like 28, Fig. l) strikes a. ston 29 in the shape of the slideway, whereupon the shaft first drops and is then given an additional short turn to restorethe brushes to their initial position. At the same time a circuit including the rotary magnet 475 is closed which extends from the negative pole through 4:77, 182, e81, 483, 175 to the positive pole.

The rotary magnet 17 5 now receives impulses until the spring box is completely Wound up and the toothed wheel like 8, Fig. 1) is returned to its initial position. As soon as this is the case the contact 463 is opened to de-energize therelay462 which results in the circuit of the uncoupling magnet 423 being opened at contact 463 and i the circuit of the rotary magnet 475 beijng opened at contact 483. The group selector has now been restored to its normal position. 4 g Y Fig. 9] shows circuits by whiclnin cases in which acalling party who has been connecte'd through to a group selector hangs up his receiver withoutsending in numerical impulses, any movement of the group selec tor is prevented from taking place. The circuit in Fig; 9is arranged so that'the first operating magnet 500 that receivesnumetrical impulses will only receive an impulse if at least two impulses are sent in, the first of these two impulses taking no effect on the operating magnet.

u The operation of the circuit isas follows:

\Vhen' a calling p'arty'is connected through to the selector the impulse relay 405 attracts its armature and CODttlClZjflOG cl osesthe cirto the positive pole.

cuit of the release relay507 wliich extends from the negative pole" through 506-, 507 508 contact 509 and thus p'repares'a circuitfor a relay 510.- The changeover relay 511is not energizedat the first' energization of the impulse relay 505 because contact 512 short circuits the relay 511. When a series of numerical impulses is sent in the first interruption of the current through 505 results in the opening of the short-circuit of the relay 511 at contact 512. The relay 511 is energized and at its contact 513 prepares a circuit for the relay 510 which is closed at contact 514; when the relay 510 is energized on the first de-energization of the relay 505.

The relay 510 being now energized in the circuit extending from the negative pole through 514, 513, 509 to the positive pole now keeps itself looked through its contact 515 and when the next interruption of the current flowing through the relay 505 occurs which is caused by the second numerical impulse, the first operating magnet 500 of the group selector receives an impulse that flows from the negative pole through 518, 519, 517, 520, 500 to the positive pole:

taken place.

The relay 5'07 closes When the circuits of the group selector or connector are arranged in this manner a subscriber who is connected through to the selector or connector and who abandons the connection without working his dial will only causeabrief energization ot the relay 511 totahe place by the dropping backof the relay 505. The relays 511, 507immediately drop back again without any movements of the selector or connector having As regards the construction of the switches it is to be noted that panel type contact banks can be used in which the selecting of the division of bank contact sets desired for the connection is eilected by a rotary motion" instead of a vertical motion.

In this modification the-brush carrier would motion fol-lowedby a slower trunk hunting motion. I 1 a 1 The numerical impulse receivers may be divided up into a selector for' the numerical selecting function (that isa switch that re ceives the numerical impulses) which selects a high speed non-in'i'merically controlled switch that first moves at a high speed and thenat a lower speech I I claim zw 1 In a telephone exchange system, a pl-urality' of, groups of lines,-a selector switch having wipers cooperating with said'lines,

means for rendering" said lines busy, a device for producing numerical impulsesgim'eans in said selector operable in ac'cordal ice with numerical impulses produced for causing said wipers toselect a certain group of lines,

means responsive to the busy condition of all the lines insaid group for causing said wipers in a continuous motion to' pass over the lines insai'd group, a wiper carrier provided with arresting surface'sg an arresting member adapted to cooperate with a said surface for stopping said:- wipers after; they to claim 1, characterized by a carrier on which said wipers are mounted, said brush carrier being rotated in response to numer ical impulses and longitudinally moved during the line selecting operation,-

execute a switch straight line trunk hunting 5. In a telephone exchange system, a plurality of lines divided into groups, a selector switch having wipers cooperating with said lines, means for rendering said lines busy, a numerical impulse-producing device, means responsive to the operation of said device for moving said wipers at a low rate of speed to select a certain group of lines, means responsive to the busy condition of all the lines in said group for moving said Wipers at a relatively high rate of speed over the lines in said group andinto operative relation with the lines in another group, a wiper carrier provided with arresting surfaces, an arresting member adapted to cooperate with a said surface for stoppingsaid wipers after they have passed over the last line of a busy group, and means operable thereupon for moving said wipers at a relatively low rate of speed to select an idle line in the last mentioned group.

6. In a telephone exchange system, a plurality of lines divided into groups, means for rendering said lines busy, a selector having Wipers cooperating with said lines, a numerical impulse-producing device, means responsive to the operation of said device for operating said selector to move its wipers in a vertical direction into cooperative relation with a certain group of lines,

means responsive to the busy condition of all the lines insaid group for moving said wipers in a rotary direction and at a relatively high rate of speed past all the lines in said group, and means operative thereupon for rotating said wipers at a relatively low rate of speed into contact with an idle line in another group.

7. In a telephone exchange system, a plurality of lines, a selector switch having wipers cooperating with said lines, a calling line, a numerical calling device associated with said line, means for variably operating said selector switch in accordance with said numerical calling device to movewith its wipers onto a certain line, means for operatively associating said calling line with said said device in accordance with at least a ser es or two impulses, a power device for moving said wipers, a wiper carrier provided with arresting surfaces and an arrest lines, a line finder with wipers for connecting said selector switch to a calling line, means for moving said wlpers in a continuone motion until they reach. a calling line, a

toothed member adapted to move with said wipers, a wiper stopping member which engages a tooth of acid toothed member to stop the line finder wipers on the calling line, an electromagnet forv operating said stoppingrmember, means cooperating with said electromagnet for accelerating the stopping action of said stopping member, a device for producing numerical impulses, means in said selector operable in accordance with numerical impulses produced for causing said wipers to select a certain group of lines, means responsive to the busy condition of all thelines in said group for causing said wipers to pass in a-continuous motion over the lines in said group, a wiper carrier in the selector switch provided with arresting surfaces, and an arresting member adapted to cooperate with said surface for stopping the selector switch wipers after they have passed over the last busy line in said group. I

In testimony whereof I have aflixed my signature.

I FRITZ ALDENDORFF;

selector switch only after the operation of 

